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A Morisi

Publications and source records attributed to A Morisi.

8 recordsLinked to original sources
PubMed1987

Repression of quiescence-specific polypeptides in chicken heart mesenchymal cells transformed by Rous sarcoma virus.

Chicken heart mesenchymal cells do not proliferate in medium of physiological composition containing plasma (S. Balk, Proc. Natl. Acad. Sci. USA 77:6606-6610, 1980). To understand the molecular events involved in cell quiescence and in the initiation of cell division under physiological conditions, we examined the differences in the patterns of protein synthesis of quiescent, hormone-stimulated, and Rous sarcoma virus-transformed chicken heart mesenchymal cells. We describe the expression of a 20,000-kilodalton (kDa) polypeptide actively synthesized by quiescent cells but not by their transformed counterparts. Normal chicken heart mesenchymal cells stimulated with epidermal growth factor and insulin also repressed the synthesis of the 20,000-kDa polypeptide while actively growing but synthesized increasing amounts of the protein at high cell density (confluence). The synthesis of the 20,000-kDa protein is not restricted to chicken heart mesenchymal cells, since confluent, density-arrested chicken embryo fibroblasts also expressed high levels of the protein. Transformed chicken heart mesenchymal cells and embryo fibroblasts did not synthesize the protein even at high cell density. The 20,000-kDa polypeptide accumulated in the culture medium.

Animals↗
PubMed1985

Heparin-treated, v-myc-transformed chicken heart mesenchymal cells assume a normal morphology but are hypersensitive to epidermal growth factor (EGF) and brain fibroblast growth factor (bFGF); cells transformed by the v-Ha-ras oncogene are refractory to EGF and bFGF but are hypersensitive to insulin-like growth factors.

Chicken heart mesenchymal cells do not proliferate in culture medium containing heat-defibrinogenated plasma but proliferate briskly when incubated with epidermal growth factor (EGF) or brain fibroblast growth factor (bFGF) plus insulin-like growth factors (IGFs) or when infected with sarcoma or erythroblastosis viruses. When infected with the retrovirus MC29, which bears a v-myc oncogene, chicken heart mesenchymal cells proliferate at a more modest rate and become morphologically transformed. Heparin at 25 microgram/ml causes these MC29-transformed cells to become proliferatively quiescent and to assume a normal morphology. Heparin-treated MC29-infected cells are, however, 100 times more sensitive to EGF than are their normal, uninfected counterparts. MC29-infected cells appear, likewise, to be hypersensitive to bFGF and to PDGF preparations but not to insulin. We hypothesize, therefore, (i) that heparin prevents the generation by cells of a mitogen from plasma protein precursors in the culture medium; (ii) that the v-myc oncogene renders cells hypersensitive to EGF, bFGF, PDGF, and the putative plasma-protein-derived mitogen; and (iii) that MC29-infected cells must proliferate in order to manifest the transformed morphology. Chicken heart mesenchymal cells infected with a recombinant spleen necrosis virus containing a v-ras oncogene are morphologically transformed but proliferate only sluggishly in plasma-containing medium without added mitogenic hormones. Heparin does not significantly affect their behavior. They are refractory to mitogenic stimulation by EGF or bFGF suggesting that ras proteins mediate the effects of receptors for these hormones. The SNV/v-ras-infected cells proliferate briskly, however, in response to hyperphysiological concentrations of insulin, an IGF surrogate, and are considerably more sensitive to this IGF mitogenicity than are their normal, uninfected counterparts.

Animals↗
PubMed1984

Morphological transformation, autonomous proliferation and colony formation by chicken heart mesenchymal cells infected with avian sarcoma, erythroblastosis and myelocytomatosis viruses.

Normal chicken heart mesenchymal cells at low density in monolayer culture in plasma-containing medium have a polygonal shape and are proliferatively quiescent. The combination of epidermal growth factor and insulin at hyperphysiological concentration, an insulin-like growth factor surrogate, causes these cells to assume a fusiform shape and to increase 40-fold in number during four days of incubation. These mitogenic hormones do not, however, induce normal chicken heart mesenchymal cells to form colonies in agarose suspension culture. Chicken heart mesenchymal cells infected with the Schmidt-Ruppin or Prague-A strains of Rous sarcoma virus or with the Fujinami or Y73 avian sarcoma viruses assume spindle and round shapes, increase 50-100 fold in number during four days of monolayer culture in the absence of mitogenic hormones and form macroscopic colonies during 3-4 days of agarose suspension culture. The autonomous (mitogenic hormone-independent) proliferation, in monolayer culture, of cells infected with temperature-sensitive transformation mutants of Rous sarcoma virus (tsNY68, tsNY72, tsLA24, tsLA29) is temperature-sensitive. Chicken heart mesenchymal cells infected with avian erythroblastosis virus assume spindle shapes and proliferate in monolayer culture at a rate comparable to that of sarcoma virus-infected cells but do not, however, form colonies in agarose suspension culture. Cells infected with the myelocytomatosis virus MC29 assume stellate shapes and increase 18-fold in number during four days of monolayer culture. Cells infected with the myelocytomatosis virus MH2 assume fusiform shapes and increase fourfold in number during four days of monolayer culture. Neither MC29 nor MH2 renders chicken heart mesenchymal cells capable of colony formation in agarose suspension culture. Infection with avian leukosis viruses (RAV-1, RAV-2, RPL-42) or with transformation-defective mutants of Rous sarcoma virus (tdNY105, 107, 109) does not affect the morphology or proliferative behavior of chicken heart mesenchymal cells. Monolayer culture of chicken heart mesenchymal cells in plasma-containing medium appears, therefore, to define the ability of onc genes of acute transforming avian retroviruses to induce autonomous (mitogenic hormone-independent) cell proliferation, the essential characteristic of neoplasia. The differences in transformed morphology and rates of autonomous proliferation between cells infected with different acute transforming retroviruses probably reflects differences in the modes of action of the transforming proteins encoded by the onc genes of the respective viruses.(ABSTRACT TRUNCATED AT 400 WORDS)

Alpharetrovirus↗
PubMed1984

Somatomedins (insulin-like growth factors), but not growth hormone, are mitogenic for chicken heart mesenchymal cells and act synergistically with epidermal growth factor and brain fibroblast growth factor.

Chicken, ovine or human growth hormones have no mitogenic effect on chicken heart mesenchymal cells, which are proliferatively quiescent at low culture densities in medium containing heparinized, heat-defibrinogenated rooster plasma at 10%. Sm-C/IGF-I (15 ng/ml; 2 nM), MSA/rIGF-II (50 ng/ml; 7 nM), insulin (10,000 ng/ml; 1750 nM) or proinsulin (16,000 ng/ml; 1750 nM), however, cause these cells to increase threefold in number during four days of incubation. While EGF alone at 100 ng/ml causes threefold multiplication at four days and brain FGF causes a sixfold increase, EGF acts synergistically with Sm-C/IGF-I, MSA/rIGF-II, insulin or proinsulin to cause 18-fold multiplication, and brain FGF acts synergistically with IGFs to cause 20-fold multiplication. EGF and brain FGF, however, show no mitogenic synergy. Addition to the plasma-containing culture medium of a monoclonal antibody to Sm-C/IGF-I nearly abolishes the mitogenic effect of added EGF or brain FGF but does not affect the autonomous (mitogenic hormone-independent) proliferation of RSV-infected chicken heart mesenchymal cells. These findings support the somatomedin hypothesis for growth hormone action and suggest that potentiation of the activity of other mitogenic hormones, like EGF and FGF, makes a significant contribution to control of cell proliferation by the GH/IGF axis.

Animals↗
PubMed1984

Phorbol 12-myristate 13-acetate, ionomycin or ouabain, and raised extracellular magnesium induce proliferation of chicken heart mesenchymal cells.

Cultured chicken heart mesenchymal cells are proliferatively quiescent at low densities in medium containing plasma at 10%. Mitogenic hormones like epidermal growth factor and insulin-like growth factors cause these cells to proliferate very actively, as does infection with avian sarcoma viruses, erythroblastosis virus, or myelocytomatosis virus. We have found that the combination of phorbol 12-myristate 13-acetate (PMA), ionomycin or ouabain, and raised extracellular magnesium, likewise, causes these cells to proliferate very actively. Although these agents have no significant effect when acting singly, the combination of PMA at 100 ng/ml and 0.5 microM ionomycin induces a 6-fold increase in cell number at 4 days, and the combination of PMA, ionomycin, and 5.6 mM magnesium induces 12-fold multiplication. Likewise, PMA plus 1 microM ouabain induces 3-fold multiplication, whereas the combination of PMA, ouabain, and magnesium induces 6-fold multiplication. The tumor promoter PMA, like diacylglycerol released by breakdown of plasma membrane phosphatidylinositol diphosphate, is known to activate the serine- and threonine-specific intracellular enzyme kinase C. The divalent cation ionophore ionomycin is known to carry calcium into cells down an electrochemical gradient, and the Na+,K+-ATPase inhibitor ouabain appears to elevate intracellular calcium by means of a sodium-mediated exchange mechanism. Magnesium, like calcium, is known to enter cells passively down an electrochemical gradient and to be involved in the regulation of many key intracellular reactions. Our findings with PMA, ionotropes, and magnesium support a hypothesis that diacylglycerol-mediated activation of kinase C plus cellular divalent cation influx and/or mobilization, caused by the action of mitogenic hormones or the protein products of onc genes, are key events in the initiation of cell replication.

Animals↗
PubMed1968

[Not Available].

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History, Modern 1601-↗
PubMedDate not supplied

[Progresses in the preparation of protein hydrolysates for the treatment of diseases related to aminoacid metabolism disorders (author's transl)].

A method is described for the preparation of a protein hydrolysate to be used in diets for the treatment of the diseases primarily related to disorder of amino acid Metabolism. The method is based on the use of ion-exchange resins to avoid the use of mineral acids so that the time of hydrolysis is reduced to 7 hrs and aminoacids destroyed in the usual industrial preparations are protected. Yields of 70% are obtained with an hydrolysis ratio of 90%. These results allow the preparation of hydrolysates with a high chemical score in which the aminoacid responsible for the diseases primarily related to disorder of amino acid Metabolism symtoms have been removed.

Amino Acid Metabolism, Inborn Errors↗